Bicycle wireless electronic derailleur

ABSTRACT

A bicycle wireless electronic derailleur, comprising a support body, a movable body, comprising a chain guide, actuation means configured to move the movable body with respect to the support body, comprising an electric motor, a controller of the electric motor, a wireless communication device, part of or in communication with the controller, configured to receive gearshifting request signals from a wireless transmitter and housed in a first casing, and a bicycle movement detector configured to emit a wake signal for the wireless communication device. The movement detector is at least partially housed in at least one second casing different from the first casing, and is in communication through at least one cable with the wireless communication device.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Italian Patent Application No.10201.6000131314, filed on Dec. 27, 2016, which is incorporated hereinby reference as if fully set forth.

FIELD OF INVENTION

The present invention relates to a bicycle wireless electronicderailleur.

BACKGROUND

With reference to FIG. 1, a motion transmission system in a bicycle 1000comprises a chain 100 extending between toothed wheels 1002, 1004associated with the axle of the pedal cranks 1006 and with the hub 1008of the rear wheel 1010. When—as in the case shown—at at least one of theaxle of the pedal cranks 1006 and the hub 1008 of the rear wheel 1010there is an assembly of toothed wheels 1002, 1004 comprising more thanone toothed wheel 1002, 1004, and the motion transmission system istherefore provided with a gearshift 1012, a front derailleur 1014 and/ora rear derailleur 1016 are provided for.

Hereinbelow in the present description and in the attached claims, thetoothed wheels 1002 associated with the axle of the pedal cranks 1006are also called chainrings, and the toothed wheels 1004 associated withthe hub 1008 of the rear wheel 1010 are also called sprockets.

In case of an electronic gearshift, each derailleur 1014, 1016 comprisesa guide element 1018, 1020,—also known as chain guide or, in case of arear derailleur, rocker arm—movable to displace the chain 100 among thetoothed wheels 1002, 1004 in order to change the gear ratio, and anelectromechanical actuator to move the chain guide 1018, 1020.

Each electromechanical actuator in turn typically comprises a motor,typically a suitably powered electric motor, coupled with the chainguide 1018, 1020 through a linkage such as an articulated parallelogram,a rack system or a worm screw system. However, in principle the chainguide 1018, 1020 could also be directly connected to the electric motor.

Typically, the electric motor is provided with a gear reductionmechanism. The assembly of electric motor and gear reduction mechanismis referred to hereinafter as geared motor. The actuator typicallyfurther comprises a sensor or transducer of the position, speed,acceleration and/or direction of rotation, of the rotor of the motor orof any movable part downstream of the rotor, down to the chain guide1018, 1020 itself. It is worthwhile emphasizing that slightly differentterminology from that used in this context is also in use.

Control electronics changes the gear ratio automatically, for examplebased on one or more detected variables such as the travel speed, thecadence of rotation of the pedal cranks, the torque applied to the pedalcranks, the slope of the travel terrain, the heart rate of the cyclistand similar, and/or the gear ratio is changed based on commands manuallyinput by the cyclist through suitable control members, for examplelevers and/or buttons, typically provided on one or two manual controldevices 1022 mounted on the handlebars 1024 of the bicycle 1000.

Typically, the derailleur 1014, 1016 includes a support body 1026, 1028that is configured to be attached to the frame of the bicycle 1000, andthe chain guide 1018, 1020 connected to the support body 1026, 1028 bymeans of two connecting rods or arms, the ends of which are pivoted tothe support body 1026, 1028 and to the chain guide 1018, 1020 to formthe aforementioned articulated parallelogram.

The geared motor drives the articulated parallelogram open and closedand as a consequence the displacement of the chain guide 1018, 1020among the toothed wheels 1002, 1004.

As an alternative or in addition to an electronic gearshift, modernbicycles are often provided with electric, electronic andelectromechanical apparatuses, including suspensions, lighting systems,sensors of the travel speed, of the cadence of rotation of the pedalcranks, of the torque applied to the pedal cranks, of the slope of thetravel terrain, of the heart rate of the cyclist and similar, satellitenavigation systems, training devices, anti-theft systems, cyclecomputers capable of providing information about the status of thebicycle, of the cyclist and/or of the route, etc.

All of the aforementioned electric, electronic and electromechanicalapparatuses consume electrical energy, supplied by one or more batterypower supply units, possibly rechargeable. Although it is possible toexploit, for recharge, the movement of the bicycle itself through adynamo, it is nevertheless important to save as much energy as possible.The aforementioned apparatuses are therefore in general provided notonly with a proper on/off switch, but also with a standby mode.

Under wait or standby or sleep or low consumption mode, a condition inwhich an electric, electronic or electromechanical device is notoperating, but is ready to switch from a temporary inactivity state toan operating mode is meant to be indicated; in standby mode, only thosecircuits that allow the device to start upon receiving commands thatinvolve the actuation thereof are typically kept operating, thus thereis a low consumption of electrical energy.

Vice-versa, in an operating mode, an electric, electronic orelectromechanical device is ready to receive commands or in generalinputs and to carry out tasks, even though it can be engaged only inwaiting for commands and inputs, without carrying out any specific task.

The switching from a standby mode to an operating mode is indicatedherein as wake of a device. More in general, under wake of a device itis meant to encompass maintaining a device in an operating mode,preventing it from entering a standby mode. A same signal or a similarsignal can be used in both cases.

For bicycle apparatuses that can be reached by the cyclist, such as forexample the manual control devices associated with the handgrips of thehandlebars or cycle computers fixed to the handlebars or in the frontpart of the frame, the wake signal is easily associated with thepressing of a button or with the actuation of a lever by the cyclist.

For apparatuses arranged in parts of the bicycle remote from the handsof the cyclist, such as for example the derailleurs, brakes andsuspensions, the wake signal can be a signal, specific or not, receivedfrom another on-board apparatus, for example one of the just mentionedones. Thus, for example, the actuation of an upward gearshifting requestlever by the cyclist can be used to generate a wake signal of theelectronics of the manual control device of which the lever is partand/or of an electronic derailleur to which the signal is intended andis transmitted.

However, in case of apparatuses connected in a wireless network, thereexists the problem that at least the wireless communication device of anapparatus must be in operating mode in order to be able to receive asignal from another apparatus. Therefore, it is not possible to exploita remote signal as a wake signal.

In such an operating mode, the wireless communication device has a highconsumption of electrical energy, and therefore it is desirable thatsuch a mode is limited to when the bicycle is in use.

In particular, the wireless electronic derailleurs are provided with awireless—for example radio or infrared—communication device thatreceives the gearshifting request signals from the manual controldevices fixed to the handgrips of the handlebars and/or from a controlunit that receives them from such manual control devices or thatprocesses them automatically.

When the bicycle is in use, the wireless communication devices of theelectronic derailleurs must therefore be always in operating mode inorder to be ready to receive such gearshifting request signals at anymoment. Only when the bicycle is stopped for a prolonged period, thewireless communication devices of the electronic derailleurs can enterstandby mode.

It is therefore necessary for the wireless electronic derailleur to beitself equipped with a detector of the movement of the bicycle, so thatthe signal emitted therefrom can be used as a wake signal.

In order to distinguish a prolonged stop, for example in a parking slotor a garage, from a temporary stop, for example at a traffic light, itis possible to use a timer and/or to use the same signal emitted by themovement detector to prevent the standby mode to be entered, namely asan anti-sleep signal.

It should be understood that the other devices of the wirelesselectronic derailleurs, for example the controllers of the motors, caninstead enter standby mode also during the use of the bicycle and bewoken by a wake signal generated by the wireless communication deviceswhen they receive the gearshifting request signals.

US2001/048211 A1 discloses a bicycle gearshift comprising a sensor ofthe rotation of a crank arm or of a pulley of a rear derailleur, saidrotation being interpreted as a movement of the motion transmissionchain from the crank arms to the rear wheel. In the case of the crankarm, the sensor is of a potentiometric type. In the case of the rearderailleur, the sensor comprises a C-shaped magnetic element fixed tothe pulley and at least one Hall-effect sensor or a Reed relay mountedon a half-cage supporting the pulleys of the chain-tensioner of the rearderailleur.

U.S. Pat. No. 8,909,424 B2, on which the preamble of claim 1 is based,discloses a bicycle wireless electronic derailleur, comprising a controlunit which includes a wireless receiver that receives shift requestsignals from a wireless transmitter, wherein the control unit includes aCPU and a wake sensor operatively associated to the CPU. The derailleurincludes a base part attachable to the bicycle, a movable part, a chainguide attached to the movable part and a linkage that interconnects thebase part to the movable part to enable the movable part to moverelative to the base part by means of a motor; the control unit with thewake sensor is housed within the movable part. The wake sensor is of avibrational type, but the document generically discloses that magneticreed switches configured to detect magnets attached to moving elementsof the bicycle might be used.

SUMMARY

The problem at the basis of the present solution is to implementimproved wireless electric derailleur.

In an aspect the solution relates to a bicycle wireless electronicderailleur, comprising:

a support body, configured to be mounted on a bicycle frame at anassembly of coaxial toothed wheels of the bicycle,

a movable body, comprising a chain guide,

actuation means configured to move the movable body with respect to thesupport body, comprising an electric motor,

a controller of the electric motor,

a wireless communication device, part of or in communication with thecontroller, configured to receive gearshifting request signals from awireless transmitter, the wireless communication device being housed ina first casing,

a bicycle movement detector configured to emit a wake signal for thewireless communication device,

wherein the movement detector is at least partially housed in at leastone second casing different from the first casing, and is incommunication through at least one cable with the wireless communicationdevice.

In this manner, any intervention of check-up, adjustment and replacementof the movement detector can take place without having to break theintegrity and the watertight seal of the casing housing the wirelesscommunication device and possible other—electronic and not—components ofthe derailleur.

The wireless transmitter is external to the derailleur, in particular itis part of a manual control device that generates the gearshiftingrequest signals or of a control unit that receives the gearshiftingrequest signals from one or more manual control devices or thatprocesses them automatically.

The at least one communication cable is preferably an electric cable,but it can also be a fiber optic cable.

Preferably, the communication through at least one cable between thewireless communication device and the movement detector is provided withat least one pair of matching removable connectors.

In this manner, the movement detector can be easily replaced without anykind of intervention on the wireless communication device or otherelectronic components of the derailleur.

Preferably, the movement detector comprises at least one magnet thatgenerates a magnetic field and at least one magnetic field sensor, themagnetic field detected by the sensor being different depending onwhether the bicycle is moving or stationary.

Preferably, both the magnet and the sensor are attached to the chainguide, at least the sensor being housed in the at least one secondcasing and being in communication through the at least one cable withthe wireless communication device.

Preferably, the sensor is fixed to a first plate of the chain guide.

More preferably, when the derailleur is a front derailleur, the sensoris fixed to an inner plate of the chain guide.

In the present description and in the attached claims, under “inner”,the side closest to the bicycle frame in the mounted condition of thederailleur is meant to be indicated, while under “outer”, the sidefurthest from the bicycle frame in the mounted condition of thederailleur is meant to be indicated.

Vice-versa, when the derailleur is a rear derailleur, the sensor ispreferably fixed to an outer plate of the chain guide.

Preferably, the sensor is fixed at a respective recessed seat or at anotch in the first plate of the chain guide.

Preferably, the magnet is fixed to a second plate of the chain guide,wherein the mutual position of the magnet and of the sensor is fixed,and the sensor is immersed in the magnetic field generated by themagnet, and wherein a length of a closed loop path intended for a motiontransmission chain of the bicycle, at least at a predetermined gearratio, is immersed in the magnetic field generated by the magnet, sothat, if in said path length there is at least one actual chain portion,the sensor detects the magnetic field perturbed by said actual chainportion.

The motion transmission chain of a bicycle is typically made of aparamagnetic or ferromagnetic material, and its segments or portionsfollowing one another while the chain is moving perturb the magneticfield generated by the magnet, changing the field lines thereof, in avariable manner.

In this manner a direct check of the actual motion of the motiontransmission chain—in turn indicative of the movement of the bicycle—isadvantageously carried out, instead of inferring it from the movement ofthe members engaged therewith.

Preferably, the path length has a length different from the length of achain link or of a multiple thereof.

In the present description and in the attached claims, under “chainlink”, the configuration of minimum length that is repeated in atransmission chain is meant to be indicated.

More preferably, the path length has a shorter length than the length ofa chain link.

In such cases, in the path length there is, at each time, a chainportion corresponding to only one chain link segment, or to one or moreentire links plus a link segment, respectively. Given that the chainlinks do not have a uniform mass distribution and therefore do not havea uniform magnetic permeance, if the chain moves in its intended closedloop path, the detected magnetic field is variable over time, while ifthe chain is stationary—or even absent, the detected magnetic field isconstant. Vice-versa, if the path length were the same length as thelength of a chain link or a multiple thereof, the chain portion actuallyin such a path length would always be the same as a whole, although withits sub-portions displaced, and the detected magnetic field would benearly constant, making it more difficult to detect the movement of thechain.

More preferably, the path length is of a length comparable to the lengthof a joint element of a chain link.

In a particularly preferred manner, the path length passes through aspace between the magnet and the sensor. Such a configuration ispreferable because it maximizes the perturbation of the magnetic fieldgenerated by the magnet by the chain.

Preferably, the magnet and the sensor are aligned along a directionperpendicular to the tangent to said path length. In this manner, sincethe chain links and their segments detected at each time follow oneanother along such a tangent, the detection capability is optimal.

More preferably, the magnet and the sensor are aligned along a directionparallel to the rotation axes of the toothed members engaged by thechain. In this manner, the chain is left free to vibrate and/or tochange the shape of the closed loop path.

Preferably, the magnet is fixed at a respective recessed seat or at anotch in the second plate of the chain guide.

Preferably, the magnet and the sensor are fixed at correspondingpositions of opposite plates of the chain guide.

In embodiments, the derailleur is a rear derailleur and the chain guidecomprises two pulley-carrying plates.

In this case, preferably the magnet and the sensor are fixed to saidpulley-carrying plates at corresponding positions.

Preferably, the magnet and the sensor are fixed to the pulley-carryingplates at the toothing of a pulley, more preferably of the upper pulleyof the chain tensioner.

In embodiments, the derailleur is a front derailleur.

In embodiments, the magnet and the sensor are so sized that at least onesecond length of a second closed loop path intended for the motiontransmission chain of the bicycle, at a second predetermined gear ratio,is also immersed in the generated magnetic field.

In this manner, a same magnet/sensor pair can detect the movement of thechain also as the gear ratio changes, and therefore as the specificclosed loop configuration that the chain takes up changes.

Alternatively, different magnet/sensor combinations for the various gearratios can be provided for.

Preferably, therefore, the detector comprises a magnet/sensorcombination for each chainring of the gearshift.

In this way it is possible to monitor a length of the specific closedloop path that the chain forms for each chainring engaged by the chainwith a specific magnet/sensor combination. Such a path indeed changesquite remarkably as the engaged chainring changes. The engaged chainringbeing equal, the closed loop path of the chain changes depending on theengaged sprocket, however the change in the path length at the frontderailleur is negligible.

Thus, in embodiments, the detector comprises at least one second magnetthat generates a second generated magnetic field, and at least onesecond magnetic field sensor, wherein the mutual position of the secondmagnet and of the second sensor is fixed and the second sensor isimmersed in the second generated magnetic field, wherein a second lengthof a second closed loop path followed by the motion transmission chainof the bicycle, at a second predetermined gear ratio, is immersed in thesecond generated magnetic field, so that, if in said second path lengththere is at least one actual chain portion, the second sensor detectsthe second magnetic field perturbed by said actual chain portion.

As an alternative or in addition, the detector comprises at least onesecond magnet that generates a second generated magnetic field, themutual position of the second magnet and of said sensor is fixed, andthe sensor is also immersed in the second generated magnetic field,wherein a second length of a second closed loop path followed by themotion transmission chain of the bicycle, at a second predetermined gearratio, is immersed in the second generated magnetic field, so that, ifin said second path length there is at least one actual chain portion,the sensor detects the second magnetic field perturbed by said actualchain portion.

As an alternative or in addition, the detector can possibly additionallycomprise at least one second magnetic field sensor, wherein the mutualposition of the magnet and of the second sensor is fixed, the secondsensor is immersed in the generated magnetic field, wherein a secondlength of a second closed loop path followed by the chain, at a secondpredetermined gear ratio, is immersed in the generated magnetic field sothat, if in said second path length there is at least one actual chainportion, the second sensor detects the magnetic field perturbed by saidactual chain portion.

In other embodiments, when the derailleur is a rear derailleur and thechain guide comprises two pulley-carrying plates and two pulleyspivotally supported between the pulley-carrying plates, the magnet isfixed to a first pulley of the chain guide, and the sensor is fixed to apulley-carrying plate in such a position as to be periodically immersedin the magnetic field generated by the magnet during the rotation of thefirst pulley.

In this manner, the sensor detects the magnet when the latter enters itsdetection field, and thus the movement of the motion transmissionchain—in turn indicative of the movement of the bicycle—is monitoredthrough the movement of the pulley.

The first casing can be part of or fixed to the support body.

Alternatively, the actuation means comprise an articulated parallelogramlinkage, and the first casing is part of or is fixed to a connecting rodof the linkage.

Preferably, the first casing further houses the electric motor.

In other embodiments, the movement detector could comprise another kindof sensor for detecting the movement of the bicycle chain. For example,it could be an optical sensor such as a photoelectric cell, the lightbeam of which is blocked by the passage of the joints of the chain, butnot by the passage of the inner and outer small plates of the chainlinks; or wherein a light beam generated by a source adjacent to theoptical sensor is reflected by a small mirror fixed to a pulley of therear derailleur only when the small mirror passes in front thereof.

More in general, it could be a movement detector not based on thedetection of the movement of the chain, for example a clinometer, agyroscope, a vibration sensor, etc.

The movement detector need not necessarily be fixed to the chain guideof the movable body of the derailleur, rather can be fixed to otherparts of the derailleur, or be fixed to the bicycle frame.

In another aspect the solution relates to a wireless electronicderailleur of a bicycle gearshift, comprising:

a support body, configured to be mounted on a bicycle frame at anassembly of coaxial toothed wheels of the gearshift,

a movable body, comprising a chain guide,

actuation means configured to move the movable body with respect to thesupport body, comprising an electric motor,

a controller of the electric motor,

a wireless communication device, part of or in communication with thecontroller, configured to receive gearshifting request signals from awireless transmitter, the wireless communication device being housed ina first casing,

a bicycle movement detector configured to emit a wake signal for thewireless communication device, wherein the movement detector comprisesat least one magnet that generates a magnetic field and at least onemagnetic field sensor, the magnetic field detected by the sensor beingdifferent depending on whether the bicycle is moving or is stationary,

wherein both the magnet and the sensor are attached to the chain guide,the sensor being housed in a second casing different from the firstcasing and being in communication through at least one cable with thewireless communication device.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present solution will becomeclearer from the following detailed description of some preferredembodiments thereof, made with reference to the attached drawings. Thedifferent features illustrated and described with reference to theindividual configurations can be combined as desired. In the followingdescription, for the illustration of the figures, identical or similarreference numerals are used to indicate constructive or functionalelements with the same function of analogous function. In the drawings:

FIG. 1, already described in detail, is a side view of a bicycleprovided with a gearshift according to the prior art,

FIG. 2 is a schematic representation of a detector used in someembodiments of the solution, and of its geometric relationship with themotion transmission chain of the bicycle,

FIG. 3 is a perspective view of the detector and of a chain portion,

FIG. 4 is a partial cross-sectional view across the detector and thechain portion of FIG. 3,

FIGS. 5, 6 and 7, 8 are views corresponding to FIGS. 4 and 5 in twodifferent positioning conditions of the chain,

FIG. 9 illustrates the main components of a wireless electronicderailleur,

FIG. 10 is a perspective view of a front derailleur according to anembodiment of the solution,

FIGS. 11 and 12 are perspective views of a rear derailleur according toan embodiment of the solution,

FIGS. 13 and 14 are partial cross-sectional views across the derailleurof FIGS. 11 and 12, corresponding to different positioning conditions ofthe chain,

FIGS. 15 and 16 are perspective views of a rear derailleur according toanother embodiment of the solution, and

FIGS. 17 and 18 are partial cross-sectional views across the derailleurof FIGS. 15 and 16, corresponding to different positioning conditions ofthe chain.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First, a movement—as well as presence/absence—detector 10 of a motiontransmission chain 100, used in some embodiments of the solution, isdescribed, which detector is shown in an entirely schematic manner inFIG. 2.

The detector 10 comprises a magnet 12 and a magnetic field sensor 14.The magnet 12 generates a magnetic field, indicated herein as generatedmagnetic field. The magnet 12 can be a permanent magnet or anelectromagnet.

The magnet 12 and the sensor 14 are arranged in a fixed mutual position.The sensor 14 is immersed in the magnetic field generated by the magnet12.

The magnet 12 and the sensor 14 are arranged sufficiently close to aposition where the chain 100 must pass, when it engages with apredetermined chainring 1002 and sprocket 1004. In greater detail, themotion transmission chain 100 of the bicycle 1000, at a predeterminedgear ratio, is wound in a closed loop—as can be seen in FIG. 1, alreadydescribed in the introductory part of the present description. The paththat the chain 100 is intended to follow is shown schematically in FIG.2 and indicated therein with reference numeral 130.

A length 140 of the closed loop path intended for or followed by thechain 100, at least at a predetermined gear ratio, is immersed in themagnetic field generated by the magnet 12.

If the chain 100 were absent, in said path length 140 there would nolonger be any chain portion, and the sensor 14 would detect the magneticfield generated by the magnet 12, not perturbed. The output of thesensor 14 would therefore have a first constant value.

Vice-versa, when the chain extends between the predetermined chainring1002 and sprocket 1004, in said path length 140 there is actually achain portion indicated with 150, 152, 154 in FIGS. 3-8, respectively.It should be noted that only a portion 110 of the chain 100, althoughlonger than the chain portion 150, 152, 154, is shown in FIGS. 3-8, indifferent positions.

Given that the chain 100 is typically made of a paramagneticmaterial—typically steel—or, less frequently, of a ferromagneticmaterial, the chain portion 150, 152, 154 actually arranged in the pathlength 140 perturbs the magnetic field generated by the magnet 12,changing the field lines thereof.

The sensor 14 therefore detects the magnetic field perturbed by thechain portion 150, 152, 154, of average intensity different from that ofthe generated magnetic field, not perturbed. The output of the sensor 14therefore has a value different from the first constant value.

The amount of the perturbation of the magnetic field depends on whichchain portion is actually in the path length 140 at a given moment, inparticular on the magnetic permeance of the chain portion. Byconstruction, the mass distribution and therefore the magnetic permeanceis not uniform along the chain 100. Under “mass distribution”, in thepresent description and in the attached claims, the way in which thematerial forming the chain portion changes and/or is arranged in spaceis meant to be indicated.

More in particular, the field lines of the magnetic field generated bythe magnet 12 find a favored path in the paramagnetic or ferromagneticmaterial, having high magnetic permeance, and therefore the distributionof the field lines depends on the mass distribution of paramagnetic orferromagnetic material in the space detected by the sensor 14; on theaverage, the sensor 14 however detects how much mass of paramagnetic orferromagnetic material is present.

As an example, each of the links 160 of the chain 100 shown in FIGS.3-8, wherein a link is understood as a configuration of minimum lengththat is repeated in the chain 100, comprises:

a pair of metallic outer small plates 162, 164 or outer links, paralleland spaced apart by a first distance,

a pair of metallic inner small plates 166, 168 or inner links, paralleland spaced apart by a second distance shorter than the first distance,

an intra-link joint element 170, which connects first ends of the outersmall plates 162, 164 and first ends of the inner small plates 166, 168,

an inter-link joint element 172, which connects second ends of the outersmall plates 162, 164 with second ends of inner small plates 166′, 168′of an adjacent link or, vice-versa, which connects second ends of theinner small plates 166, 168 with second ends of outer small plates 162′,164′ of an adjacent link.

The joint elements 170, 172 are typically equal to each other. Also forthis reason, according to a different terminology each of the pairs ofsmall plates —outer 162, 164 or inner 166, 168, respectively—could alonebe called chain link.

Each joint element can comprise, for example, a bush formed by twocollars 174, 176 extending towards one another about holes 178, 180 ofthe two inner small plates 166, 168, a rivet 182 extending in the bushand having riveted ends, and a possible rotatable roller 184 extendingoutside of the bush formed by the collars 174, 176 and having thefunction of reducing the friction with the teeth of the toothed members1002, 1004 with which the chain 100 engages in the motion transmissionsystem, teeth that consecutively insert in the space between the pairedinner small plates 166, 168 and in the space between the paired outersmall plates 162, 164.

The rivet 182 can be replaced by a pin as one piece with one of theouter small plates 162, 164 and having only one riveted end, and/orother configurations of the chain 100 can be provided.

As stated above, the intensity of the perturbed magnetic field, detectedby the magnetic field sensor 14, depends on the distribution of mass andof magnetic permeance of the chain portion 100 actually present, at agiven moment, in the path length 140. In particular, in the case of thechain 100 described above:

when the chain portion 150 actually in the path length 140 is at a jointelement 170, 172, as shown in FIGS. 3 and 4, the intensity of theperturbed magnetic field, detected by the sensor 14, is maximum and theoutput signal of the sensor 14 has a peak (or vice-versa a valley);

when the chain portion 152 actually in the path length 140 is at thecentral region of a pair of metallic inner small plates 166, 168, asshown in FIGS. 5 and 6, the intensity of the perturbed magnetic field,detected by the sensor 14, is minimum and the output signal of thesensor 14 has a valley (or vice-versa a peak);

when the chain portion 154 actually in the path length 140 is at thecentral region of a pair of metallic outer small plates 162, 164, asshown in FIGS. 7 and 8, the intensity of the perturbed magnetic field,detected by the sensor 14, has a value comparable to, although slightlygreater than, the minimum, and the output signal of the sensor 14 againhas a valley (or vice-versa a peak).

When the cyclist pedals, the chain 100 moves along the intended closedloop path 130: at the path length 140 there are, at subsequent moments,different chain portions corresponding, as far as the mass distributionand the magnetic permeance are concerned, to the portions 150, 152, 150,154, the sequence endlessly repeating itself (neglecting the “falselink” for closing the chain, slightly different from standard links).

The perturbed magnetic field detected by the sensor 14 is thereforevariable over time. In particular, the perturbed magnetic field detectedby the sensor 14 has a pattern that is substantially periodic androughly oscillating between the aforementioned maximum value at thejoint elements 170, 172 and the aforementioned minimum value at thecentral region of a pair of small plates 166, 168 or 162, 164,respectively (neglecting their different distribution of mass andmagnetic permeance).

If, on the other hand, the chain 100 is stationary, the magnetic fielddetected by the sensor 14 is constant.

Therefore, the detector 10 can be advantageously used as a detector ofthe movement of the chain 100. Since it carries out a direct check ofthe actual movement of the motion transmission chain 100, instead ofinferring it from the movement of the toothed members engaged therewith,such a movement detector 10 is extremely accurate.

Electronics of the detector 10 or associated therewith is configured todetermine that the chain 100 is moving when the output signal of thesensor 14 is variable over time, and to determine that the chain 100 isstationary when the output signal of the sensor 14 has a second constantvalue different from the first constant value indicative of the absenceof chain.

In the above it has been assumed that the path length 140 is of a lengthquite shorter than the length of a chain link 160, namely that the pathlength 140 or the sensor 14, respectively, is suitably sized based onthe distribution of mass and magnetic permeance in a chain link 160.

However, this is not strictly necessary. If in the path length 140 thereis, at each time, a chain portion that is longer than those describedabove, although shorter than a chain link 160, or a chain portion thatis as long as one or more entire links plus a link segment, then themass distribution—and the magnetic permeance—in the path length 140 isstill variable over time when the chain 100 is moving, although withvariations that are less easily distinguishable.

If the path length 140 were the same length as the length of a chainlink 160 or of a multiple thereof, the mass distribution—and themagnetic permeance—in the path length 140 at each moment would always beequivalent, although displaced if the chain 100 is moving, and themagnetic field detected by the sensor 14 would be nearly constant,making it more difficult to detect the movement of the chain 100. Inthis case, the detector 10 could in any case be used, outside of thescope of the claimed solution, as a presence detector of the chain 10.

As discussed in the introductory part of the present description, theindication of the actual movement of the chain 100 provided by thedetector 10 can be advantageously exploited to provide a wake signal.For this specific purpose, the detector 10 can in particular be used ina wireless electronic derailleur, as will be described hereinafter.

The indication of the actual movement of the chain 100 provided by thedetector 10 can be advantageously exploited also, for example, toprevent an attempt to change gear ratio when the detector 10 detectsthat the chain 100 is absent or stationary, in order to protect themotion transmission system, as well as for any other purpose.

From what has been described above it can easily be understood that thevariability of the perturbed magnetic field detected by the sensor 14can also be exploited to estimate a speed of the movement of the chain100 from a repetition period of the output signal of the sensor 14, oran approximation thereof, during an observation time window. Indeed, thehigher is the speed of the movement of the chain 100, the higher will bethe frequency of appearance of the aforementioned maximum values at thejoint elements 170, 172, and of the aforementioned minimum or almostminimum values at the small plates 162-168 will be.

The aforementioned electronics can therefore be configured to calculateor estimate the speed of the movement of the chain 100. By operatingdirectly on the chain 100, instead of inferring the speed thereof fromthe rotation speed of a toothed member engaged therewith, for example apulley of the rear derailleur 1016, the movement detector 10 proves tobe advantageously very accurate.

In a practical embodiment, the magnetic field sensor 14 can comprise,for example, a Hall effect sensor or a Reed relay. Magnetic fieldsensors of the aforementioned kind are well known.

The output of the sensor 14 can be a two-levels one depending on whetherthe magnetic field in which it is immersed is below or above apredetermined threshold, or the output of the sensor can be an analoguesignal. The detector 10 can moreover possibly comprise pre-processingelectronics of the output signal of such a sensor 14, for example foramplification, filtering and/or approximation, quantization,binarization, digitalization, inversion, etcetera.

Observing a characteristic configuration of the output signal of thesensor 14, such as for example a peak or a valley, for example a peakrepresentative of the passage of the chain portion 150, the electronicscan also estimate a stroke of the chain. The stroke is indeed a functionof the position of such a characteristic configuration in a length ofthe output signal of the sensor 14 and/or a function of a displacementof the characteristic configuration during an observation time window ofthe output signal of the sensor 14.

Again with reference to FIG. 2, advantageously the path length 140passes through a space between the magnet 12 and the sensor 14, so as topass in between them as shown. Such a configuration maximizes theperturbation of the generated magnetic field by the chain portion 150,152, 154 actually present in the space.

Preferably, the magnet 12 and the sensor 14 are aligned along adirection perpendicular to the tangent t to the path length 140. In thisway, since the chain links 160 and their segments or portions 150, 152,154 detected, at each time, follow one another along such a tangent t,the detection capability is optimal.

More preferably, the magnet 12 and the sensor 14 are aligned along adirection n parallel to the rotation axes of the toothed members engagedby the chain 100, such as the chainrings 1002, the sprockets 1004 andthe pulleys of the rocker arm 1020 of the rear derailleur 1016. In thisway, the chain 100 is left free to vibrate and/or to change the shape ofthe closed loop path 130.

Because as the gear ratio, namely the chainring 1002—sprocket 1004 pair,changes, the chain 100 takes up a different closed loop configurationand thus has a different intended path, it is possible to size themagnet 12 and the sensor 14 in such a way that at least one secondlength 140A of a second closed loop path 130A followed by the chain 100,at a second predetermined gear ratio, is also immersed in the magneticfield generated by the magnet 12. In this way, a same magnet/sensor paircan detect the presence and/or the movement of the chain 100 at thevarious gear ratios.

Alternatively, different magnet/sensor combinations can be provided forthe various gear ratios.

Thus, the detector 10 can possibly comprise a second magnet 12A, asshown, which generates a second generated magnetic field and a secondmagnetic field sensor 14A, wherein the mutual position of the secondmagnet 12A and of the second sensor 14A is fixed, and the second sensor14A is immersed in the second generated magnetic field, wherein a secondlength 140A of a second closed loop path 130A followed by the chain 100,at a second predetermined gear ratio, is immersed in the secondgenerated magnetic field so that, if and when a second chain portion isactually in said second path length 140A, the second sensor 14A detectsthe second magnetic field perturbed by the second chain portion.

In this way, the detector 10 can be advantageously used to check notonly whether the chain 100 is broken or dropped and/or is moving, butalso which the actual gear ratio is or, respectively, which toothedwheel 1002, 1004 is currently engaged by the chain 100. Indeed,depending on the actual gear ratio, the chain 100 will extend along oneof the closed loop path 130 and the second closed loop path 130A, andthus will be detected by one of the two sensors 14 or 14A.

As an alternative or in addition, for the same purpose the detector 10can possibly comprise the second magnet 12A that generates the secondgenerated magnetic field, but associated with the same sensor 14 as themagnet 12, namely wherein the mutual position of the second magnet 12Aand of said sensor 14 is fixed and the sensor 14 is also immersed in thesecond generated magnetic field. Also in this case, the second length140A of the second closed loop path 130A followed by the chain 100, atthe second predetermined gear ratio, is immersed in the second generatedmagnetic field, so that the sensor 14 also detects the second magneticfield perturbed by a possible chain portion 100 that is actually in saidsecond path length 140A.

As an alternative or in addition, the detector 10 can possibly comprisethe magnet 12 that generates the generated magnetic field, the sensor 14and the second magnetic field sensor 14A, wherein the mutual position ofthe magnet 12 and of the sensor 14 is fixed, and the mutual position ofthe magnet 12 and of the second sensor 14A is fixed, the sensor 14 isimmersed in the generated magnetic field, and the second sensor 14A isimmersed in the generated magnetic field, wherein the second length 140Aof the second closed loop path 130A followed by the chain 100, at asecond predetermined gear ratio, is immersed in the generated magneticfield so that, if and when a second chain portion is actually in saidsecond path length 140A, the second sensor 14A detects the secondmagnetic field perturbed by the second chain portion.

The configurations outlined above can be repeated, in any combination,for all of the gear ratios. Hereinafter, for the sake of brevity,reference will be made to the detector 10 in its basic configurationcomprising a magnet 12 and a sensor 14.

The detector 10 can be mounted at a suitable length of the closed looppath 130, 130A of the chain 100, for example by providing a suitablesupport fixed to the frame of the bicycle 1000.

In FIGS. 3-8 the magnet 12 and the sensor 14 are schematicallyillustrated, mounted on two carriers 16, 18, respectively.

The aforementioned carriers 16, 18 are in the form of two parallel andsuitably spaced apart flat walls so as to allow the passage, between themagnet 12 and the sensor 14, of the chain 100 in the preferred geometricrelationship described above, of alignment along the direction n.

The magnet 12 is supported by the carrier 16. In particular, in the caseshown the magnet 12 is glued in a through hole 20, formed in the carrier18 and better visible in FIGS. 4, 6, and 8. The hole 20 can be replacedby a recessed seat or a blind hole.

As an alternative to gluing, the magnet 12 could just be forcedly fitinto the hole 20 or fixed to the carrier 16 in a different manner, forexample welded, co-molded, or in other ways.

The sensor 14 is, in the case shown, mounted onto the carrier 18 througha casing 22 configured for being fixed to the carrier 18, and in which ahousing seat 24 is defined. It is understood that the casing 22 is madeof a suitable material so as not to interfere with the detection by thesensor 14 of the magnetic field generated by the magnet 12, possiblyperturbed by the chain portion 150, 152, 154.

The magnetic field sensor 14 is in particular embodied on a PrintedCircuit Board (PCB) 26, which can i.a. carry the electronics describedabove.

A cable (cf. the description of the following FIGS. 10-18) that carriessignals and/or power to/from the sensor extends from the board 26, asuitable passage hole being provided in the casing 22. Alternatively,outside of the scope of the claimed solution, the sensor 14 can beprovided with its own battery power supply unit and with a wirelesscommunication circuit, the cable being absent.

More specifically, the casing 22 has a T-shaped cross-section, and theseat 24 is made in a portion 28 thereof corresponding to the leg of theT. The portion 28 of the casing 22 containing the housing seat 24 isinserted in a notch 30 of a corresponding shape, formed on the top ofthe carrier 18. In particular, the wall of the carrier 18 and theportion 28 of the casing 22 have the same thickness, so that the casing22 is flush with the face of the carrier 18 facing towards the magnet12, so that the sensor 14 is in proximity of the magnet 12—and inproximity of the chain portion 150, 152, 154 when present along the pathlength 140 that extends between the magnet 12 and the sensor 14.However, the notch 30 can be replaced by a recessed seat on the oppositeface of the carrier, namely by a groove.

The casing 22 of the sensor 14 is fixed in a suitable manner to thecarrier 18. In the embodiment shown, the fixing takes place throughsuitable screws 32 extending through the portion 34 of the casing 22corresponding to the head of the T. Alternatively, the casing 22 couldbe fixed to the carrier 18 in a different manner, for example throughgluing, riveting, welding, etc.

The carriers 16, 18 could, for example, comprise two legs of a smallfork suspended in a suitable position with respect to the closed looppath 130 followed by the chain 100.

Advantageously, according to some embodiments of the solution, thedetector 10 is mounted in a derailleur 1014, 1016 of the motiontransmission system of the bicycle 100.

More specifically, the detector 10 is mounted in, or in any case isassociated with, a wireless electronic derailleur 200, of which FIG. 9illustrates the main components.

The wireless electronic derailleur 200 comprises i.a. a support body202, configured to be mounted on the frame of the bicycle 1000 at anassembly of coaxial toothed wheels 1002, 1004 of the gearshift 1012,namely at the chainrings 1002 or the sprockets 1004; a movable body 204,comprising a chain guide 206; and an electromechanical actuator 208 oractuation means 208 configured to move the movable body 204 with respectto the support body 202. The actuation means 208 comprise an electricmotor 210, typically part of a geared motor, and can comprise a linkage,such as for example an articulated parallelogram.

The wireless electronic derailleur 200 further comprises a controller240 of the electric motor 210, as well as a wireless communicationdevice 242. The wireless communication device 242 is configured toreceive gearshifting request signals 250 from a wireless transmitter252.

The gearshifting request signals 250 can be emitted by the manualcontrol devices 1022 fixed to the handgrips of the handlebars 1024and/or by a control unit of the gearshift 1012 that receives them fromsuch manual control devices 1022 or that processes them automatically.The wireless transmitter 252 can be part of the manual control devices1022 or of another component of the gearshift 1012 of which thederailleur 200 is part.

The detector 10, when it detects the movement status of the bicycle1000—in particular in the case described above inferring it from themovement status of the chain 100 —, is configured to emit a wake signal244 for the wireless communication device 242, so as to lead it into anoperating mode from a standby mode, and possibly keep it in operatingmode.

When the bicycle is in use, therefore, the wireless communication device242 of the wireless electronic derailleur 200 is constantly kept inoperating mode so as to be ready to receive the gearshifting requestsignals 250 at any moment. Only when the bicycle is stopped for aprolonged period, the wireless communication device 242 can enterstandby mode. In order to distinguish a prolonged stop, for example in aparking slot or garage, from a temporary stop, for example at a trafficlight, it is possible to use the same signal emitted by the movementdetector 10 to prevent the standby mode to be entered, namely as ananti-sleep signal; alternatively it is possible to use a specific timer(not shown).

The other devices of the wireless electronic derailleur 200, inparticular the controller 240 and/or the actuator 208, can instead enterstandby mode also during the use of the bicycle, and be woken by asecond wake signal, generated by the wireless communication device 242when it receives the gearshifting request signals 250 from the wirelesstransmitter 252.

In a per se known manner, the wireless communication device 242, thecontroller 240 and the motor 210 can be housed at various mechanicalparts of the derailleur 200. In particular, the wireless communicationdevice 242 is housed in a first casing that is fixed to or is part ofthe support body 202 or is fixed to or is part of a connecting rod ofthe articulated parallelogram linkage of the electromechanical actuator208, although these are shown as distinct components in the blockdiagram of FIG. 9.

Some exemplary embodiments of wireless electronic derailleur 200 with anassociated detector 10 will now be described.

FIG. 10 shows, as an example, a front derailleur, indicated withreference numeral 300, in which the detector 10 is mounted.

The front derailleur 300 comprises a support body 302, configured to bemounted on a bicycle frame at an assembly of chainrings 1002, a movablebody 304 comprising a chain guide 306 (in the case shown, movable bodyand chain guide coincide), and actuation means 308 configured to movethe movable body 304 with respect to the support body 302.

In the case shown, the front derailleur 300 is electronic and theactuation means 308 comprise a geared motor 310 and an articulatedparallelogram linkage 312, but the front derailleur could be madedifferently, in a per se well known manner.

The magnet 12 and the sensor 14 of the detector 10 are fixed at thechain guide 306.

The magnet 12 and the sensor 14 are, in particular, fixed atcorresponding positions of opposite plates 314, 316 of the chain guide306, so that the closed loop path 130 followed by the chain 100 passesin between them. When magnet 12 and sensor 14 are at correspondingpositions as shown, they turn out to be aligned along a directionperpendicular to the tangent to the path length that the chain 100follows between the plates of the chain guide 314 themselves.

More specifically, the magnet 12 is fixed to the outer plate 314 of thechain guide 306 and the sensor 14 is fixed to the inner plate 316 of thechain guide 306, at a projection 318 projecting upwards from the innerplate 316, so that the sensor 14 is at the same height as the magnet 12.When magnet 12 and sensor 14 are at the same height, they are alignedalong the direction parallel to the rotation axes of the chainrings1002.

The magnet 12 and the sensor 14 in the mounted positions illustratedturn out to be in an optimal mutual position and at an optimal distancefor the described operation of the detector 10.

A cable 320 connecting the casing 22 containing the sensor 14 to thesupport body 302 is also shown, in which support body 302, in theembodiment shown, the electronics of the derailleur 300 and inparticular the wireless communication device 242, as well as a possiblebattery power source unit, are housed. The cable 320 is advantageouslyprovided with a removable connector 322 configured for removableconnection with a matching connector (not visible) of the support body302, so as to facilitate a possible replacement of the sensor 14.

The detector 10 further comprises, in the embodiment shown, the secondmagnet 12A and the second sensor 14A coupled to each other, so as todetect the presence/movement of the chain 100 when it follows one of twoclosed loop paths, depending on the chainring 1002 with which itengages, in the case of a front gearshift assembly having twochainrings. The second sensor 14A is shown housed in a second casing22A, from which a cable 320A extends that is provided with a connector322A, similarly to the sensor 14. However, a single casing housing thetwo sensors could be provided for.

Also the cabled connection could follow a different scheme, for examplein which the second sensor 14A is connected to the first sensor 14 andonly the first sensor 14 is connected to the support body 302.

In the case of a front gearshift assembly having three or morechainrings, there will be a third magnet and a third sensor, or more.

All of the other magnet/sensor combinations described above are alsopossible.

FIGS. 11-14 show, as an example, a rear derailleur, indicated withreference numeral 400, in which the detector 10 is mounted.

The rear derailleur 400 comprises a support body 402, configured to bemounted on a bicycle frame at an assembly of sprockets 1004, a movablebody 404, comprising a chain guide 406, and actuation means 408configured to move the movable body 404 with respect to the support body402.

In the case shown, the rear derailleur 400 is electronic and theactuation means 408 comprise a geared motor 410 and an articulatedparallelogram linkage 412, the geared motor 410 being arranged along thediagonal of the articulated parallelogram 412, but the rear derailleurcould be implemented differently, in a per se well known way.

The magnet 12 and the sensor 14 of the detector 10 are fixed at thechain guide 406.

The magnet 12 and the sensor 14 are, in particular, fixed atcorresponding positions of opposite plates 414, 416 of the chain guide406, so that the closed loop path 130 followed by the chain 100 passesin between them. When magnet 12 and sensor 14 are at correspondingpositions, they are aligned along a direction perpendicular to thetangent to the path length that the chain 100 follows between the platesof the chain guide 406 themselves.

More specifically, the sensor 14 is fixed to the outer plate 414 orpulley-carrying plate of the rocker arm or chain tensioner or chainguide 406, and the magnet 12 is fixed to the inner plate 416 orpulley-carrying plate of the rocker arm 306.

Even more specifically, magnet 12 and sensor 14 are fixed to thepulley-carrying plates 414, 416 at the toothing 426 of a pulley 428,more preferably of the upper pulley 428 of the chain tensioner 406.

In the present description and in the attached claims, the terms “upper”and “lower” are used with reference to the normal condition of use ofthe bicycle.

In this manner, magnet 12 and sensor 14 are aligned along the directionparallel to the rotation axes of the pulleys 428, 430.

Since irrespective of the sprocket 1004 engaged by the chain 100, thelatter always follows a same length of a closed loop path that windsaround the pulleys 428, 430, the single pair formed by magnet 12 andsensor 14 turns out to be sufficient.

FIGS. 13-14 show a section through the chain guide 406 at the detector10. In FIG. 13, in the path length immersed in the magnetic fieldgenerated by the magnet 12 there is a chain portion corresponding to ajoint element 170, 172 of the chain 100. In FIG. 14, in the path lengthimmersed in the magnetic field generated by the magnet 12 there is achain portion corresponding to a pair of small plates 162-168 (the outerones 162, 164 in the case shown).

It can be seen that in the condition of FIG. 14, between magnet 12 andsensor 14 a tooth 432 of the toothing 426 of the pulley 428 is alsopartially arranged, which tooth however does not perturb the magneticfield because the pulleys 428, 430 are typically made of plasticmaterial. In any case, its contribution to the perturbation could beduly taken into account.

Also in this case a cable 420 is shown that connects the casing 22containing the sensor 14 to the outer connecting rod 413 of the linkage412, inside which in the embodiment shown the electronics of thederailleur 400 and in particular the wireless communication device 242are housed. The cable 420 is advantageously provided with a connector422 of the removable type configured for the removable connection with amatching connector (not visible) of the outer connecting rod 413, so asto facilitate a possible replacement of the sensor 14.

FIGS. 15-16 show, as an example, another rear derailleur, indicated withreference numeral 500, wherein the movement detector 10 is differentlymounted.

The rear derailleur 500 comprises a support body 502, configured to bemounted on a bicycle frame at an assembly of sprockets 1004, a movablebody 504, comprising a chain guide 506, and actuation means 508configured to move the movable body 504 with respect to the support body502.

In the case shown, the rear derailleur 500 is electronic and theactuation means 508 comprise a geared motor 510 and an articulatedparallelogram linkage 512, the geared motor 510 being arranged along thediagonal of the articulated parallelogram 512, but the rear derailleurcould be differently implemented, in a per se well known way.

The magnet 12 and the sensor 14 of the detector 10 are fixed at thechain guide 506.

In particular, the magnet 12 is fixed to one of the pulleys 528, 530 ofthe chain guide or chain tensioner or rocker arm 506, in the case shownto the upper pulley 528 of the rocker arm 506.

The sensor 14 is fixed to one of the pulley-carrying plates 514, 516, inthe case shown to the outer plate 514 of the chain tensioner 506, insuch a position as to be periodically immersed in the magnetic fieldgenerated by the magnet 12 during the rotation of the pulley 528 towhich it is fixed.

In this manner, the sensor 14 detects the magnet 12 when the latterenters its detection field, and thus the movement of the motiontransmission chain 100—in turn indicative of the movement of the bicycle1000—is monitored through the movement of the pulley 528.

During the rotation of the pulley 528, the magnet 12 and the sensor 14periodically come to be at corresponding positions.

Even more specifically, the magnet 12 is fixed to the upper pulley 528along a radial and at a certain distance from the rotation axis, in aradially inner position with respect to the toothing 526. The sensor 14is fixed to the outer plate 514 along a radial and substantially at thesame distance with respect to the rotation axis of the upper pulley 528.In the angular position of the upper pulley 528 wherein magnet 12 andsensor 14 are in corresponding positions, they are aligned along adirection parallel to the rotation axes of the pulleys 528, 530.

Also in this case, because irrespective of the sprocket 1004 engaged bythe chain 100, the latter always follows a same length of the closedloop path that winds around the pulleys 528, 530, the single pair formedby magnet 12 and sensor 14 turns out to be sufficient.

FIGS. 17-18 show sections through the chain guide 506 at the detector10, in different rotation conditions of the upper pulley 528.

In particular, in FIG. 17 the upper pulley 528 is rotated into anangular position wherein the magnet 12 and the sensor 14 are atcorresponding positions.

In FIG. 18, on the other hand, the upper pulley 528 is rotated into anangular position wherein the magnet 12 and the sensor 14 are not atcorresponding positions; the magnet 12, as a consequence, is notvisible.

It should be noted that in this case the portion 28 of the casing 22housing the sensor 24 is housed in a groove of the pulley-carrying plate514, so that a thin wall 534 extends in front of the sensor 14, in adirection towards the magnet 12. If such a wall 534 is made ofparamagnetic or ferromagnetic material, its contribution to theperturbation of the magnetic field generated by the magnet 12 is in anycase constant, and therefore can be duly taken into account.

Also in this case a cable 520 is shown connecting the casing 22containing the sensor 14 to the outer connecting rod 513 of the linkage512, inside which in the embodiment shown the electronics of thederailleur 500 and in particular the wireless communication device 242are housed. The cable 520 is advantageously provided with a connector522 of the removable type configured for removable connection with amatching connector (not visible) of the outer connecting rod 513, so asto facilitate a possible replacement of the sensor 14.

As stated in the introductory part, the movement detector 10 couldcomprise a non-magnetic sensor for detecting the movement of the chain100 of the bicycle.

For example, it could be an optical sensor arranged in a similar mannerto the embodiments of FIGS. 2-14, such as a photoelectric cell the lightbeam of which is blocked by the passage of the joints 170, 172 of thechain 100, but not by the passage of the inner small plates 162, 164 andouter small plates 166, 168 of the links 160 of the chain 100—the lightsource and the photoelectric cell being aligned along a directionperpendicular with respect to that of the elements 12, 14 shown, namelyalong a direction perpendicular both to the direction t and to thedirection n defined above.

Alternatively, it could be an optical sensor arranged in a similarmanner to the embodiment of FIGS. 15-18, wherein a light beam generatedby a source adjacent to the optical sensor is reflected by a smallmirror fixed to a pulley 528, 530 of the rear derailleur only when thesmall mirror passes in front of it.

More in general, it could be a movement detector not based on thedetection of the movement of the chain, for example a clinometer, agyroscope, a vibration sensor, etc.

The movement detector 10 need not necessarily be fixed—as a whole or inpart—to the movable body 204, 304, 404, 504 of the derailleur 200, 300,400, 500 as in the embodiments shown, rather it can be fixed to otherparts of the derailleur, or it can be fixed to the bicycle frame.

The communication cable 302, 302A, 402, 502 between the detector 10 andthe wireless communication device 242 can be an electric cable or it canbe a fiber optic cable.

The wireless communication device 242 can be housed in a differentcasing than the one indicated above in the various embodiments, and ingeneral it can be part of or fixed to the support body, part of or fixedto any component of the linkage, or even part of or fixed to the movablebody of the derailleur.

What is claimed is:
 1. Bicycle wireless electronic derailleur,comprising: a support body configured to be mounted on a frame of abicycle at an assembly of coaxial toothed wheels of the bicycle, amovable body, comprising a chain guide, actuation means configured tomove the movable body with respect to the support body, comprising anelectric motor, a controller of the electric motor, a wirelesscommunication device, part of or in communication with the controller,configured to receive gearshifting request signals from a wirelesstransmitter, the wireless communication device being housed in a firstcasing, a bicycle movement detector configured to emit a wake signal forthe wireless communication device, wherein the movement detector is atleast partially housed in at least one second casing different from thefirst casing, and is in communication through at least one cable withthe wireless communication device.
 2. The derailleur according to claim1, wherein the communication through at least one cable between thewireless communication device and the movement detector is provided withat least one pair of matching removable connectors.
 3. The derailleuraccording to claim 1, wherein the movement detector comprises at leastone magnet that generates a magnetic field and at least one magneticfield sensor, the magnetic field detected by the sensor differsaccording to whether the bicycle is moving or stationary.
 4. Thederailleur according to claim 3, wherein both the magnet and the sensorare attached to the chain guide, at least the sensor is housed in the atleast one second casing and being in communication through the at leastone cable with the wireless communication device.
 5. The derailleuraccording to claim 3, wherein the sensor is fixed to a first plate ofthe chain guide.
 6. The derailleur according to claim 5, wherein thederailleur is a front derailleur and the sensor is fixed to an innerplate of the chain guide.
 7. The derailleur according to claim 5,wherein the derailleur is a rear derailleur and the sensor is fixed toan outer plate of the chain guide.
 8. The derailleur according to claim5, wherein the sensor is fixed in one of a respective recessed seat anda notch in the first plate of the chain guide.
 9. The derailleuraccording to claim 5, wherein the magnet is fixed to a second plate ofthe chain guide, wherein a mutual position of the magnet and of thesensor is fixed, and the sensor is immersed in the magnetic fieldgenerated by the magnet, and wherein a length of a closed loop pathfollowed by a motion transmission chain of the bicycle, at least at apredetermined gear ratio, is immersed in the magnetic field generated bythe magnet, so that, if in said path length there is at least one actualchain portion, the sensor detects the magnetic field perturbed by saidactual chain portion.
 10. The derailleur according to claim 9, whereinthe path length passes through a space between the magnet and thesensor.
 11. The derailleur according to claim 4, wherein the magnet andthe sensor are fixed at corresponding positions of opposite plates ofthe chain guide.
 12. The derailleur according to claim 9, wherein thederailleur is a rear derailleur and the chain guide comprises twopulley-carrying plates, wherein the magnet and the sensor are fixed tosaid pulley-carrying plates at corresponding positions at the toothingof a pulley, preferably of the upper pulley of the chain tensioner. 13.The derailleur according to claim 9, wherein the derailleur is a frontderailleur.
 14. The derailleur according to claim 1, wherein thederailleur is a rear derailleur and the chain guide comprises twopulley-carrying plates and two pulleys pivotally supported between thepulley-carrying plates, the magnet is fixed to a first pulley of thechain guide, and the sensor is fixed to a pulley-carrying plate in sucha position as to be periodically immersed in the magnetic fieldgenerated by the magnet during the rotation of the first pulley.
 15. Thederailleur according to claim 1, wherein the first casing is fixed tothe support body.